The demonstration on the video is both impressive and serves as documentation if you want to experiment with the Lively Kernel yourself. As it is, the Lively Kernel is a good prototype but if the performance is improved a bit and the programming environment and IDE (which is like Squeak Smalltalk, only for Javascript) continues to improve, then Lively Kernel is on my (personal) radar for something that I will use in the future.

I remember getting a Xerox 1108 Lisp Machine in 1982 and I also wanted the optional Smalltalk environment which was not in the budget. However, a sales engineer at Xerox did let me use Smalltalk for a month on a trial basis. It is amusing to be able to get a smalltalk like programming environment like Lively Kernel for free that is hosted in a web browser. Something about Moore's Law and also about free software projects...

Off course, by far the best free Smalltalk experience is Squeak but Lively Kernel is still very cool, if only for its possible future use of quickly writing web interfaces using existing web services, etc.